Connecting the lifecycles of galaxies and their central black holes

连接星系及其中心黑洞的生命周期

• 批准号: MR/Y019539/1
• 负责人: James Aird
• 金额: $ 75.59万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FY019539%2F1
• 关键词: Connecting; lifecycles; galaxies; their; central

Understanding why galaxies - including our own galaxy, the Milky Way - look the way they do is a vital part of our mission to understand the Universe around us. At the centre of most, if not all, galaxies (including the Milky Way) lies a supermassive black hole, with a mass that is millions to billions of times the mass of the Sun. These black holes appear to be crucial component of galaxies, determining much of their structure and evolution, although how and why is still unclear. As a Future Leaders Fellow, my team and I are determining how these black holes grow, when this growth occurs within the lifecycle of a galaxy, and how these black holes affect the galaxies they lie in.Galaxies have long lives. They evolve slowly as the gas within them forms stars, these stars age over billions of years, and the overall shape and structure of a galaxy gradually changes. By comparison, the massive black holes at their centres appear to grow relatively rapidly, in short-lived "growth spurts" lasting at most a few million years. During these growth spurts, material falls towards the black hole, heats up and can produce huge amounts of radiation spanning the entire electromagnetic spectrum. A galaxy with such a growing black hole is described as having an "active galactic nucleus" or AGN. Over recent years, astronomers have started to understand the structure of the material close to a black hole that forms an AGN and how these structures produce radiation at different wavelengths - including X-rays, optical and infrared light and radio emission. These structures result in a wide range of observed phenomena in different galaxies, all of which can be associated with an AGN powered by a growing supermassive black hole. However, we do not know how these structures change over millions of years or longer for an individual AGN, over timescales relevant for galaxy evolution.My team and I are developing new techniques to connect the lifecycles of galaxies and their central black holes, probing timescales of millions to billions of years. Our studies reveal how material is brought into the centre of a galaxy, how this material forms an AGN, how the AGN changes and eventually fades over the course of many millions of years, what impact the AGN has on the galaxy during this time, and how often this whole process repeats throughout the lifetime of a galaxy.Studying processes on such long timescales is extremely challenging. We cannot watch a single galaxy over this time, so instead, we are using new surveys of the sky that provide "snapshots" of many millions of galaxies and their AGN, each at a different life stage. We have developed new methods to extract information from these static snapshots and are building new models to describe the lifecycles of individual AGN and explain what we see in these snapshots. We are also studying the properties of galaxies with (and without) AGN to determine whether certain types of galaxies are more likely to have an AGN. In doing so, we can determine which physical mechanisms within galaxies are responsible for driving material into their central regions and fuelling the periods of AGN activity. Our work combines data from an array of new astronomical surveys. We are using new surveys that are underway with the premier ground-based telescopes, measuring the spectrum of light from large samples of galaxies that is imprinted with vital information on their lifecycles, combined with new X-ray imaging of the sky provided by the recently launched eROSITA telescope as well as existing infrared data and new surveys at radio wavelengths that can be combined to track the variation in AGN structure within these galaxies.

理解为什么星系——包括我们自己的星系，银河系——看起来是这样的，是我们理解我们周围的宇宙的任务的重要组成部分。在大多数（如果不是全部的话）星系（包括银河系）的中心都有一个超大质量黑洞，其质量是太阳质量的数百万到数十亿倍。这些黑洞似乎是星系的关键组成部分，决定了它们的大部分结构和进化，尽管如何以及为什么还不清楚。作为一名未来领袖研究员，我和我的团队正在研究这些黑洞是如何成长的，在星系的生命周期中，这种成长发生在什么时候，以及这些黑洞是如何影响它们所在的星系的。星系的寿命很长。随着它们内部的气体形成恒星，它们慢慢进化，这些恒星的年龄超过数十亿年，星系的整体形状和结构逐渐发生变化。相比之下，它们中心的大质量黑洞似乎生长得相对较快，在短暂的“生长突增”中最多持续几百万年。在这些快速增长的过程中，物质落入黑洞，被加热，并产生大量的辐射，覆盖整个电磁波谱。有这样一个不断增长的黑洞的星系被描述为具有“活动星系核”或AGN。近年来，天文学家已经开始了解形成AGN的黑洞附近物质的结构，以及这些结构如何产生不同波长的辐射-包括x射线，光学和红外光以及无线电发射。这些结构导致了在不同星系中观察到的各种现象，所有这些现象都与由不断增长的超大质量黑洞提供动力的AGN有关。然而，我们不知道这些结构如何在数百万年或更长时间内对单个AGN发生变化，在与星系演化相关的时间尺度上。我和我的团队正在开发新技术，将星系的生命周期和它们的中心黑洞联系起来，探索数百万到数十亿年的时间尺度。我们的研究揭示了物质是如何进入星系中心的，这些物质是如何形成AGN的，AGN在数百万年的过程中是如何变化并最终消失的，在这段时间里AGN对星系有什么影响，以及整个过程在星系的整个生命周期中重复的频率。在如此长的时间尺度上研究过程是极具挑战性的。在这段时间里，我们无法观察到单个星系，因此，我们正在使用新的天空调查，为数百万个星系及其AGN提供“快照”，每个星系都处于不同的生命阶段。我们已经开发了从这些静态快照中提取信息的新方法，并正在构建新的模型来描述单个AGN的生命周期，并解释我们在这些快照中看到的内容。我们也在研究有（和没有）AGN的星系的特性，以确定某些类型的星系是否更有可能有AGN。通过这样做，我们可以确定星系内部的哪种物理机制负责将物质驱动到它们的中心区域，并为AGN活动周期提供燃料。我们的工作结合了一系列新的天文调查的数据。我们正在使用最先进的地面望远镜进行的新调查，测量来自大型星系样本的光谱，这些样本上印着它们生命周期的重要信息，结合最近发射的eROSITA望远镜提供的新的天空x射线成像，以及现有的红外数据和新的无线电波长调查，可以结合起来跟踪这些星系中AGN结构的变化。